Recently the portable lighting device market has enjoyed excellent growth. However, during this period there has been a growing ground swell of negative consumer attitudes towards certain aspects of these lighting devices which could eventually culminate in limiting further growth of the market. For example, there appears to be concern about
(a) increased cost and complexity of these devices with diminishing "apparent value"; PA0 (b) product malfunctioning including failure to make electrical contact, bulb out of focus, defective switching, etc.; PA0 (c) bulb and power source replacement is complicated and/or difficult; PA0 (d) poor design, particularly as to location, actuation and movement of the switch; and PA0 (e) excessive bulb failure and/or bulb maladjustment relative to the reflector attributed to variations in bulb length, bulb terminal and/or the fit of the bulb, with the screw shell and bumper block assemblies. PA0 (a) the head assembly contains the electrical contact, switching and bulb contact elements that cooperate to change the position of the bulb depending on the presence or absence of the power source; and PA0 (b) the body assembly provides a portion of the handle and has provisions for containing the power source and maintaining one terminal of the power source in continuous electrical contact with a bulb retainer while the other power source terminal is in electrical contact with a contact disc. PA0 (a) the head assembly contains the electrical contact, switching, and bulb positioning components and the handle base; PA0 (b) the body assembly is devoted exclusively to providing a portion of the handle and to containing the power source and maintaining the power source in continuous electrical contact with the light component and the electrical contact element in the head assembly; PA0 (c) the head assembly and body assembly are secured together by a series of living hinges and corresponding seats, to assure substantially uniform electrical contact between one terminal of the power source and the contact disc, and between the second power source terminal and the light source; PA0 (d) the slope of the handle base on the head assembly is such that the toggle switch assembly which is located in the handle and generally above the bulb pivots in an arc transverse to the beam of light where the arc is from between 15.degree. to about 30.degree., the slope of the handle is up to about 45.degree. to the axis of the reflector; PA0 (e) electrical contact between the switch assembly and the bulb is by means of an electrical contact strip which at one end engages the bulb at its base by means of a bulb restrictor having a biasing flex element, which holds the bulb base against a movable bulb retainer that has prongs slidably mounted in slots of the reflector adjacent the core, while the other end of the strip is preloaded against a foot element in the switch assembly; PA0 (f) the base of the bulb retainer has a seat member for the bulb terminal with two legs extending below the base which define the contact area for the central power source terminal spring, which passes through an aperture in the electrical contact disc; the second spring terminal of the other power source makes electrical contact with the contact disc; the contact disc also provides a contact base for the contact knee element of the electrical contact strip; PA0 (g) the switch assembly leg engages one end of the electrical contact strip which is substantially parallel to the tangent line at the center of the arc defined by the rotation of the switch assembly, thereby resulting in a mechanical advantage of movement relative to the switch assembly of approximately one; PA0 (h) neither the bulb nor the bulb retainer are fixedly secured in the core of the reflector, but rather are dynamically mounted and free to move, depending on the presence or absence of the power source; yet, both are constantly under restriction either from the engagement of the biasing element in the bulb restrictor and/or from the force applied to the bulb retainer base by the power source terminal spring; thus, this mode of dynamic bulb positioning protects the bulb in the absence of the power source, achieves optimum bulb focus relative to the fixed reflector in the presence of a power source, and assures that bulb movement occurs substantially in the axial plane and not laterally; PA0 (i) the electrical contact strip is provided with a preload force in the "off" position such that inadvertent actuation of the switch assembly is minimized, while the potential travel of the contact strip is substantially greater, i.e., up to 50% greater, than the gap between the electrical contact strip and the contact disc; this over-travel is compensated for by the flexing of a knee member in the contact strip that undergoes up to a 40.degree. change when the switch assembly moves from the "off" position to the "on" position.
Most portable lighting devices today are assembled by threading the head assembly into the body assembly. The amount of force used in assembling these two components to "tighten down" often determines whether effective electrical contact is made between the power source and the electrical contact elements. Thus, in addition to being a costly way of assembling, this arrangement inherently has a built-in variable that can adversely affect electrical contact and performance of the device, i.e., the extent to which the two units are screwed together becomes critical. Ideally, the electrical contact should be based on a pre-set condition that accommodates power source dimensional variables. These pre-set conditions are preferably relatively constant from one lighting device to another, and should not allow for variation by the consumer during power source replacement and/or bulb replacement. In addition, these pre-set conditions should preferably accommodate the variations in battery terminal length and bulb dimensional variations.
Heretofore, most lanterns have secured the bulb in a fixed position substantially free from movement. Generally this was achieved by the use of a metallic insert in the reflector core generally described as a screw shell which held the bulb in the reflector core and provided the means for electrical contact with the switch assembly. A second element, generally described as a bumper block, engaged the screw shell by means of threading into the screw shell, contact with the bulb terminal being made by means of a metal spring fixedly secured into the bumper block. The spring in the bumper block served a dual function of making electrical contact with the bulb terminal as well as functioning as a kind of shock absorber for the bulb. The bumper block comprises generally a non-conductive core element in contact with a metal disc member which is seated in the head assembly substantially with no axial movement. Heretofore the contact disc has been in continuous electrical contact with the terminal springs of the power source and in electrical contact with the contact strip when the switch assembly is moved to the "on" position. Thus, the spring action of the terminal springs has traditionally been limited to making electrical contact with the disc and has not been employed to make contact with the bulb directly. The bumper block spring/bulb base arrangement is such that the bulb can become tilted in the screw shell, resulting in less than optimum focus.
Up to the present there has been little consideration given to the optimum means for effecting electrical contact between the switch assembly, the bulb, and the power source while maintaining the bulb in focus. Certain arrangements used heretofore have been observed to eventually fail to make effective reliable contact either with the bulb and/or the power source. For example, those arrangements that rely on a sliding-type movement for the contact strip to engage the bulb appear to have inherent performance problems. Similarly, those arrangements which permanently affix the contact strip to the screw shell or other bulb holding means appear to run a risk of strip fatigue in the area of electrical contact with the screw shell, or the means for permanently affixing the strip fails resulting in an electrical short.
Contact with the power source is traditionally made by the contact strip making electrical contact with the contact disc that is in electrical contact with both power source terminals. Occasionally, these arrangements fail because the switch assembly does not move the strip sufficiently to engage the contact disc. This shortcoming is attributed in part to loss in spring action in the contact strip. Generally, these contact elements are permanently secured in the assembly and cannot be readily replaced.
Most lanterns contain some sort of a handle means which is generally an integral element of the body. As in the present invention, it may contain the switch assembly. These handles are either open, i.e., the hand can slide in from the back; or closed, i.e., the hand can grasp only by placing the fingers in from the side. The former configuration is generally preferred.